Hearing this from NASA already on reinforces what we already knew. 

New data released by NASA shows that the recent snowpack survey in the Tuolumne River Basin in California's Sierra Nevada is currently larger than the four previous years of snowpack combined. 

According to an article on NASA's website, the Airborne Snow Observatory (ASO) measured the Tuolumne Basin snowpack on April 1, 2017, at 1.2 million acre-feet. That’s enough snow to fill the Rose Bowl in Pasadena, nearly 1,600 times.

Lighter blue indicates less snow, deeper blue is more snow

The Tuolumne River Basin is a major source of water for San Francisco and California's Central Valley. 

The ASO is the only program that measures snow depth, snow water equivalent (the water contained in snow), and how much sunlight snow reflects over an entire basin, using two scientific instruments — a scanning lidar and an imaging spectrometer on a King Air aircraft. The ASO flies in California, Colorado, Oregon, Nevada and Idaho.

The 2017 snow water equivalent was 21 times greater than 2015, which was the lowest snowpack on record.

NASA claims the 2017 snowpack results are close to the largest on the record. ASO results showed that Tuolumne Basin’s snowpack is twice the volume of last year's snowpack and 21 times larger than the snowpack of 2015, the lowest on record. ASO helped determine that the combined April 1 snow water equivalent of 2013 through 2016 — intense drought years for California —added up to only 92 percent of 2017's measurement.